In the conventional art, there is a technology that when a vehicle may depart from a driving lane, a braking force to wheels of the vehicle is controlled to apply a yaw moment to the vehicle, thereby preventing the departure of the vehicle from the driving, and notifying the driver of the possibility of vehicle's departure from the driving lane due to applying of the yaw moment (refer to Patent Literature 1). The Patent Literature 1 discloses that taking forward obstacles such as a parked vehicle or the like into account, a control quantity of the lane departure prevention control (threshold for departure prevention control) is changed depending upon an obstacle on the shoulder of a road, so as to carry out a lane departure prevention control.